The object of the present invention is an accessory device for skis, permitting a set of boot bindings to be mounted on a ski.
Traditionally, a boot is attached to a downhill ski by a set of safety bindings comprising a toe binding located at the front of the boot and a heel binding located at the rear thereof, the sole of said boot being rigid and pinched elastically between the toe and heel bindings.
The first point to be noted is that the area of the ski between the toe binding and the heel binding for holding the boot is made rigid by the boot when in use. In addition, the longitudinal force exerted by the heel binding on the boot tends to increase the camber of the ski.
It is therefore regrettable for ski manufacturers, who conduct highly exhaustive tests of the behavior of skis in the design phase, to see this behavior modified by attaching the boot to the ski in different ways.
Moreover, it has been suggested that cornering accuracy can be improved by reducing the width of the skis, especially in the bottom area. As a result of this reduced width, a ski boot will extend beyond the ski on both sides. Consequently, when making a turn, especially on a steep slope, the maximum angle is reduced and limited by the contact between the boot and the snow. In this case, rubbing of the external lateral portion of the boot mounted on the uphill ski can occur. To overcome this defect, which may cause the skier to fall, it has been suggested that the boot be superelevated to restore the maximum cornering angle obtained with wider skis. Different means have been suggested, and include the following: a wedge at the bases of the ski bindings, or an elevation of the binding and boot produced by interposing between the boot and ski, a plate which can also serve to absorb vibrations, as described in document CA 1 215 403.
In addition, a number of solutions have been proposed relating to the structure of either the ski or the bindings, the ski boots, or the interfaces between these various elements in order to improve the handling of the ski and thus take advantage of technical developments that have been made in skis, to ensure equal performance, easier maneuverability, and less fatigue for skiers.
To obtain such results, apart from advances in structure, design, choice of materials, technical features, dimensioning, and distribution of flexibility, one important factor has been selective elimination of certain ranges of harmful vibration as described in patents FR 2,476,495 and FR 2,575,393 issued in the name of the applicant.
It has also been suggested that the plates be connected to the skis to meet other needs. For example, to improve comfort and safety by eliminating microtraumas caused by significant impacts sustained by the legs of a skier when going over a hard snow drift or bumps that are very close together and form very hard undulations, it has been suggested to insert a type of "elastic suspension" between the ski and each of the skier's feet, said suspension taking the form of an elastic plate of the leaf spring type as described in French Patents 2,347,066 and 2,338,720, or an elastic plate mounted on coil springs or elastic plugs as described in FR 2,409,776, WO 86/04824, DE 2,259,375, and CA 1,215,403.
Document WO 83/03360 in turn describes a plate bearing boot bindings whose ends are attached to the ski and delimit together with the latter, a space filled with a shock-absorbing material. Document EP 0,182,776 describes a plate in contact with the ski in two areas.
U.S. Pat. No. 3,797,844 describes a plate for mounting bindings, one end of said plate being attached to the ski and the other being free to slide relative to the ski. It has also been suggested that a plate be mounted on the ski, said plate being designed to correct morphological deformities of the skier, for example, a difference in the lengths of his/her legs, or joint problems as described in German Patent DE 3,710,092.
It has also been suggested that plates be used to reinforce a ski locally, especially in torsion as described in U.S. Pat. No. 3,326,564.
Another use of the distribution plate was suggested to correct the position where the force generated by the skier's weight is applied, said position generally being located at a point identified on the ski by the position of the middle of the boot, so that this plate, attached to the ski at the front and rear of the bottom, divides the skier's weight into two forces applied to the front and rear quarters of the ski as described in U.S. Pat. No. 3,260,532 and French Patent 810,762.
In fact, this solution, instead of improving the handling of the ski, has been found to be rather unfavorable because it reduces the efficiency with which turns are made, making cornering more difficult to start and perform because the pressure distribution peaks on the snow are poorly positioned.